A garden tool for removing plants having roots from the ground is described in U.S. Pat. No. 5,005,888, which issued to Parks et al. Apr. 9, 1991. This document discloses a tool having a prong assembly, there being four prongs, each of which is shown to be generally in the shape of a circular cylinder, the lower edges being chamferred.
As described at column 2, lines 20 to 24the tool appears to require at least two full rotations of the prongs to assure formation of a ground plug.